thats b.s.
any iPhone 5 from verizon is cdma AND GSM. you can use CDMA on verizon, remove the SIM card and use the GSM for AT&T.
As a matter of fact EVERY SINGLE PHONE that is CDMA and LTE that is sold, is also a GSM phone.
you can't have LTE without GSM, period
the only problem wth the verizon iPhone 5 and AT&T and t-mobie was the limited number of channels. they did not have LTE HIGH SPEED channels for verizon and AT&T and t-mobile in the same phone. this means if you took your verizon iPhone to AT&T, it would work , but you would only get 4G HSPDA+ speeds and not LTE speeds.
when the 5s and 5c came out, this was fixed, and that phone had 11 or 13 channels and had AT&T and verizon and t-mobile channels in the same phone
you can bring a VERIZON iPhone 5 to AT&T but you cant bring an AT&T iPhone 5 to VERIZON